1. Field of the Invention
The present invention relates to an electronic device that has a substrate mounted with an electronic circuit and housed in a housing.
2. Description of the Related Art
Recently, various types of mobile personal computers (abbreviated as PC hereinafter), such as a so-called notebook PC that is composed of a main unit incorporating an arithmetic circuit and having a keyboard on the front surface thereof and a display unit having a display screen and being capable of folded onto the main unit and a pure-tablet (slate) PC that incorporates an arithmetic circuit and has a display screen on the front surface thereof, to which a keyboard is optionally externally connected, have come into widespread use.
Such mobile PCs are made thinner to reduce the overall size and weight while maintaining the required display screen size, whereas the mobile PCs have more capabilities to meet various needs. In particular, a cable or the like used for connecting to another device compromises the mobility of such mobile PCs, so that many mobile PCs incorporate radio communication features conforming to various standards, such as the wireless LAN and the Bluetooth (registered trademark) For example, in Japanese Patent Laid-Open No. 2003-110736, there is proposed a device that has multiple kinds of interfaces for external communication. In Japanese Patent Laid-Open No. 2004-265377, there is proposed a device that has a card slot into which various types of cards can be inserted for feature expansion.
In the case of electronic devices designed in pursuit of thinness, such as mobile PCs of the type described above, if plural components or units having different sizes are mounted on the substrate, the interior space may not be efficiently used in the thickness direction because of the difference in size between the components or units. As many compatible components, independent of the grade or destination of the electronic devices, as possible are used, and a component or unit is removed whenever it is found to be unnecessary for the relevant grade or destination of the electronic device. If plural components or units have to be removed to meet the specifications of the grade or destination of the electronic device, the workability of adapting the electronic device to the grade or destination significantly differs depending on the positions where the components or units are mounted or the like.